The mess is hitting the fan in Chicago. Lupe Fiasco also responded to Chief’s diss back:

@OsoArrogantJoJo WAS BEEFIN WITH LIL REESE N CHIEF KEEF (GBE) THATS IN THE CAR YELLING AT REESE.. JOJO DIED AFTER THIS HAPPENED.. Cashout (Jojo’s brother) was the one who dissed Chief Keef’s mother on the phone in the previous video we posted” – Goon212

“Chicago police are investigating possible connections between the Tuesday slaying of a teen rapper, a raging Englewood gang conflict and a mocking Tweet on the account of the victim’s rap rival — rising South Side star Chief Keef, sources told the Chicago Sun-Times.
Hours after the murder, on Chief Keef’s Twitter account, a message was posted saying, “Its Sad Cuz Dat N—- Jojo Wanted To Be Jus Like Us #LMAO.” LMAO is slang for “laughing my ass off.”
That Tweet drew angry responses among Chief Keef’s 224,000 Twitter followers. His account later carried Tweets claiming it had been hacked and saying, “If u dnt talk 2 me or dro my manager … it’s not real.”
Chicago police officers were on the street Wednesday night looking for Coleman’s killer. Police are looking to see if his murder is connected to an ongoing conflict in Englewood between the Gangster Disciples and Black Disciples street gangs that has been playing out in a series of threats on social media sites.
In Keef’s responses on his account, Chicago-born rap star Lupe Fiasco was called out, with the Keef account posting: “wen I see him I’ma smack him like da lil b—- he is #300.”
On his account, Fiasco, who recently told a radio station he was scared of the violence Chief Keef represents, replied “I cant go 4 that @ChiefKeef & i cant let the people i love, including you my n—-, go 4 that either. We kings not f—— savages and goons”
Later, Fiasco sounded despondent — and done with rap, Tweeting: “but my heart is broken and i see no comfort further along this path only more pain. I cannot participate any longer in this… My first true love was literature so i will return to that…lupe fiasco ends here…”